1. Field of the Invention
This invention relates to a method for separating a mixture of different plastics into each of the plastics.
2. Description of the Prior Art
Methods have been described for separating and recovering plastics from mixed plastics or a mixture of plastics and non-plastics substances using flotation as disclosed in copending U.S. patent applications, Ser. No. 443,574 filed Feb. 19, 1974, Ser. No. 443,936 filed Feb. 19, 1974, Ser. No. 443,937 filed Feb. 19, 1974, Ser. No. 469,723 filed May 14, 1974, Ser. No. 469,921 filed May 14, 1974, Ser. No. 469,922 filed May 14, 1974 and Ser. No. 469,925 filed May 14, 1974.
However, no method for separating a mixture of a polystyrene and a polyolefin such as polyethylene and polypropylene or a mixture of polyethylene and polypropylene is known due to the close similarity in physical properties, such as specific gravity and the like of these materials. Therefore, mixtures of these materials in industrial and household waste have hithertofore been disposed of.